Stamped circuitry assembly

ABSTRACT

Disclosed is a printed circuit board assembly including an integral metal stamping having a plurality of conductive circuit paths received in complementarily-shaped recesses of a dielectric substrate. The integral metallic stamping includes an improved snap action switch having an improved actuator mechanism, an improved rotary switch of the type making on/off contact during rotation thereof, and an upstanding plug-like connector member receivable in a mating female connector. Each of the switches mentioned above as well as the plug-like connector can be formed separately in different printed circuit board assemblies.

This application is a division of application Ser. No. 771,858 filedSept. 3, 1985 now U.S. Pat. No. 4,659,157.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to stamped circuitry assemblies of thetype wherein conductive traces are stamped from a metal sheet, andthereafter applied by adhesive or the like to a dielectric substrate.

2. Brief Description Of The Prior Art

Printed circuit board assemblies produced by photographic and the liketechniques are commonly employed to provide a convenient fabrication ofhigh density electrical circuits. However, it is frequently desireableto incorporate mechanical systems in the high density circuits.Conventional printed circuit board assemblies are not satisfactory forthis application, since they have a comparatively low limit to themaximum current permissible, at least in economical forms ofconstruction. Also, a direct connection between circuit elements lyingin different planes is generally impossible, so that in such cases,additional conductors have to be introduced between circuit traces andthe individual elements which do not lie in a common plane. Further,conventional printed circuit board assemblies do not provide themechanical ruggedness necessary in hybrid electro-mechanical circuitboards, particularly when the circuit is exposed to continuous vibrationin operation, especially when the circuit traces must also carry highcurrent levels which tend to degrade the mechanical strength propertiesof those traces. One example of a hybrid electromechanical device isshown in U.S. Pat. No. 3,845,256 which describes an appliance timerhaving an electric motor, a series of gears and rotating members,affixed to the surface of a single plane dielectric substrate.

Accordingly, stamped metallic circuits have been developed to providethe high current capability, mechanical ruggedness, and multiplaneconstruction needed for a given application. Examples of representativestamped metallic circuits can be found in U.S. Pat. Nos. 3,108,360;2,971,249 and 2,969,300. Typically, the conductive traces are separatelyformed, being stamped from a metallic sheet, to form labyrinthiancircuit paths. The paths may be joined by one or more separable linkingelements to form a carrier, or to strengthen the lattice network for useduring assembly of the metallic circuit. Thereafter, the metallicstamping is applied to a dielectric substrate, typically using adhesivesuitable for the purpose. In U.S. Pat. No. 3,108,360, for example, thestamped metal tracing is sandwiched between two dielectric sheets toprotect a majority of the conductive circuit paths from corrosion or thelike degradation. A similar arrangement is found in the more recent U.S.Pat. No. 4,508,399. Again the stamped metallic surface is sandwichedbetween two dielectric portions which substantially enclose the circuit,protecting it from casual damage.

Although each of the above arrangements provide otherwise convenientmeans of electrical connection to external circuit components,improvements in the electrical connectors can be made. Also, it isdesired to incorporate in an inexpensive fashion, adjustable electricalconnectors of the type frequently employed in timing and other measuringcircuits. Further, especially when employed in highly inductive loads,it is desirable to provide a snap action switch which provides improvedcircuit making stroke breaking capability. In the past, such switcheshave comprised discrete commercially available separate assemblies, suchas those shown in U.S. Pat. No. 3,362,181. Instead of employing adiscrete miniature snap action switch, it would be desirable tointegrally form a snap action switch with the stamped metallic circuit,in a single operation.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide astamped metallic circuit which is compatible with mechanical systems,and which is simply and inexpensively formed from a single stampedconductive sheet, supported by a unitary dielectric substrate.

Another object of the present invention is to provide a stamped metalliccircuit having an improved snap action switch element integrally formedwith a stamped metallic circuit.

Still another object of the present invention is to provide an improvedactuation system for use with the snap action switch referred to above.

Yet another object of the present invention is to provide an improvedelectrical plug connector integrally formed with the stamped metalliccircuit and dielectric substrate, which offers improved strength andreliability of operation.

Still another object of the present invention is to provide an improvedadjustable switch which can be simply and easily formed from theintegral stamped metallic circuit, and which requires a minimum numberof additional components.

These and other objects of the present invention are provided The snapaction switch including an elongated resilient spring plate with twoparallel elongated spaced-apart slots therein forming two outsidesupport arms and an intermediate flexing arm, a first mounting end andan opposed second free end, contact carrying means spaced from saidmounting end, the switch further including actuator means deflecting amedial portion of the plate to displace the contact carrying meansbetween first and second bistable positions. The improvement resides inthe contact carrying means disposed at said second free end; saidsupport arms each including a pair of spaced offset portions, all ofwhich extend in the same direction transverse to said spring plate; andsaid actuator means displacing said flexing arm in first and seconddirections generally transverse to the spring plate, to causedifferential bowing between said flexing arm and said support arms,whereby said contact carrying means is displaced in said first and saidsecond directions.

In addition, according to the present invention, an improved actuatormeans for the above snap action switch comprises a rigid member havingfirst and second engaging surfaces disposed on either side of saidflexing arm, mounted for pivoting in a first direction to slide saidfirst engaging surface along said flexing arm while deflecting saidflexing arm from a first to a second bistable position, and said rigidmember mounted for pivoting in a second opposed direction to impulsivelydeflect said flexing arm with said second engaging surface, from saidsecond to said first bistable position.

Also, the present invention provides a switch including a movablymounted table having a surface defining at least one path of movement, acontact pad disposed along a portion of said path, and elongatedresilient finger-like contact means having a contact surface disposed onsaid path so as to electrically engage said contact pad as said table ismoved. The improvement comprises a moveable support arm extending in adirection transverse to said path, joined at a first end to saidfinger-like contact and threadingly joined at a second end to screwadjustment means operative to reciprocate said arm in said transversedirection; and said contact having a tapered leading edge, wherebyreciprocation of said arm causes transverse displacement of saidfinger-like contact, with said finger-like contact engaging said contactpad at different points along its tapered leading edge, to thereby varythe length of the path along said contact travelled by said finger-likecontact means.

Further, the present invention provides a stamped circuitry assemblyincluding an integral metal stamping having a plurality of discreteconductive paths, a dielectric substrate having complementary recessesfor receiving said conductive paths. The improvement comprises substrateincluding an upstanding support wall; said stamping including aplurality of upstanding fingerlike male contacts overlying andcoextensive with said support wall so as to form a plug connectorslidingly receivable in a plug-receiving cavity of a mating femalereceptacle connector having a plurality of mating second contacts.

In addition, according to the present invention, stamped metalliccircuits are provided incorporating one or more of each of the abovefeatures.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, wherein like elements are referenced alike,

FIG. 1 is a perspective view of a stamped circuitry assembly accordingto the present invention;

FIGS. 2a and 2b are elevation and plan views, respectively, of thespring switch member of FIG. 1;

FIGS. 3a-3f show a sequence of operations wherein the actuator of FIG. 1deflects the spring member of FIGS. 2a, 2b between two bistablepositions;

FIG. 4 is a plan view of an actuator of FIG. 1; and

FIG. 5 is a plan view showing the rotary switch of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, and initially to FIG. 1, a stampedcircuitry assembly is indicated generally at 10. Assembly 10 includes anintegral stamped circuit 12, formed from a unitary metal sheet to have aplurality of discrete conductive paths, as well as the plug and switchcomponents described later herein. Stamped metallic surface 12 issupported by a dielectric substrate 14. Although stamped circuit 12 canbe affixed to dielectric substrate 14 using adhesives of any suitabletype, substrate 14 is preferably formed to have recesses of varyingdepths to receive the conductive paths of circuit 12 with a frictionfit. As is known in the art, stamped circuit 12 can include one or moreseparable carrier or linking members disposed at strategic placesbetween adjacent conductive paths to lend mechanical support duringfabrication of assembly 10. Since stamped circuit 12 is of a one-pieceunitary construction including several spring members, it is preferablystamped from a single sheet of spring material such as phosphor bronzeof thickness ranging between 0.005 and 0.015 inches.

The surface 16 of substrate 14 is generally of a flat planar shapehaving openings formed therein by the various circuitreceiving recesses.As can be seen in the right hand corner of substrate 14, an upstandingsupport wall 20 projects above surface 16. Support wall 20 includes aplurality of recesses 22 to receive a complementary plurality ofupstanding finger-like male contacts 24 overlying and coextensive withwall 20. Contacts 24 and support wall 20 together comprise a plug-likeconnector slideably receivable in the plug receiving cavity 26 of amating female receptacle 28. A corresponding plurality of matingcontacts are disposed in cavity 26 for mating with male contacts 24. Theplug assembly of wall 20 and contacts 24 could, if desired, be locatedin interior portions of substrate 14 to provide a convenient point ofelectrical connection to an external circuit.

A snap action switch assembly shown in the left-hand corner of FIG. 1 isindicated generally at 40. Assembly 40 includes a spring plate 42moveable between a pair of fixed contacts 44, 46. A plunger assemblyindicated generally at 48 includes projection 50 which deflects springplate 42 between two bistable positions. Spring plate 42 is shown ingreater detail in FIGS. 2a and 2b. Spring plate 42 is formed ofresilient conductive material as part of the integral stamping ofcircuit 12. Spring plate 42 has formed therein two parallel elongatedspaced-apart slots 52, 54 which form two outside support arms 56, 58 andan intermediate flexing arm 60. Spring plate 42 has a first mounting end62 and an opposed second free end 64 which establishes electricalcontact between elements 44, 46. Outside support arm 56 includes a pairof spaced apart offset portions 66, and similarly outside support arm 58includes a pair of offset portions 68. Portions 66, 68 are offset fromthe common plane of mounting end 62 and free end 64. Although, as shownin FIG. 2a, outside intermediate portions 66' 68' joining offset portion66, 68 respectively, are also offset, they can be arranged to lie in theplane of ends 62, 64.

In operation, the free end 64 of spring plate 42 moves in the directionof arrow 70 between two bistable positions, as indicated in the sequenceshown in FIGS. 3a-3f. As shown in FIG. 3a, free end 64 is in a firstbistable position so as to establish electrical connection with contact46.

Referring to FIG. 4, a plunger assembly generally indicated at 48includes a pair of projections 50a, 50b which contact the flexing arm 60so as to displace the free end 64 in first and second directionsgenerally transverse the spring plate 42. As indicated in FIG. 3a,projection 50a is advanced along flexing arm 60 in the two directionsindicated by double headed arrow 74. That is, projection 50a is advancedin a direction generally transverse to flexing arm 60, while also beingadvanced to slide along the length of the camming area 76 of flexing arm60. Thus, projection 50a deflects flexing arm 60 with a camming actionas indicated by the cross-hatched area 76 of FIG. 2a. At a criticalpoint of deflection, flexing arm 60 takes on the second bistableposition indicated in FIG. 3c owing to the differential bowing betweenflexing arm 60 and outside support arms 56, 58. Thereafter, projection50b is advanced toward flexing arm 60 so as to cause an oppositedeflection toward the first bistable position of FIG. 3a, whereuponcontact is again established with member 46 as indicated in FIGS. 3a,3f. In the preferred embodiment, the second projection 50b is advancedtoward flexing arm 60 with an impulsive movement, whereas the firstprojection 50a is moved in a slower fashion with continuous pressurebeing applied during camming with flexing arm 60. The camming operationwas found to provide a better control of flexing arm deflection,although this was not required on the return stroke of projection 50b.In either event, the immediate application in the preferred embodimentis merely insensitive to contact bounce and jitter, although otherapplications may be more critical in this regard.

Referring now to FIG. 4, plunger assembly 48 comprises an actuator arm80 pivotally mounted at 82 to dielectric substrate 14 for movement in adirection of arrow 84. Arm 80 is biased in one direction by spring 85indicated in diagrammatic form. Actuation of arm 80 is convenientlyprovided by a cam 86 pivotally mounted at 88 for movement in acounterclockwise direction. Cam 86 has a first continuous outer surfaceportion 90 for continuous camming engagement with arm 80 so as to pivotthe arm in a first counterclockwise direction. Cam 86 also includes arecess portion 92 which withdraw as the camming engagement, allowingmovement of arm 80 in a clockwise direction under the force of spring86. Thus, the camming sliding engagement with projection 50a and flexarm 60 is provided, along with an impulsive deflection of flexing arm 60by projection 50b.

As indicated in FIGS. 1 and 4, actuator arm 80 comprises a plate-likemember lying in a plane parallel to the deflection movement of springplate 42, and overlies the spring plate to provide a covering protectiontherefore. The actuator arms 50 as can be seen in FIG. 1, depends fromthe plate-like member 80 having a convenient dog-leg shape.

Referring now to FIG. 5, a rotary switch assembly is indicated generallyat 100 to include a rotatably mounted table 102 defining a circular pathof movement 104. A plate-like contact member 106 is disposed on an uppersurface 108 of table 102. Table 102 is mounted for clockwise rotationdue to a conventional pivoting means affixed to substrate 14. Contact106 has a tapered leading edge 110, which is tapered in a radial senseto provide an advantageous timing relationship as will be explainedherein. Table 102 is mounted to the underside of dielectric substrate14, and the window-like aperture 112 provides communication with path104 from components lying on upper substrate surface 16. In thepreferred embodiment, contact 106 has an upper wiping surface projectingabove upper table surface 108. Accordingly, to provide a smoothtransition a ramp-like member 114 is provided from the same metal platefrom which contact 106 is stamped. Although ramp 114 can be electricallyconnected, it is electrically isolated in the preferred embodiment.

An elongated moveable support arm 118 is connected to stamped circuit 12through a cantilever spring beam 120. As spring beam 120 flexes in thedirection of arrow 122, support arm 118 is moved in directionstransverse to path 104, as indicated by arrow 124. Support arm 118 isjoined at a first end to a finger-like contact 128 having bifurcatedcontact surfaces 130 which slide along the upper surface of ramp 114 andelectrical contact 106 in wiping electrical engagement therewith.Support arm 118 is joined at a second end to a screw adjustment assembly132 consisting of a yoke 134 integrally formed with a substrate 14 and aconventional screw member 136 having a head 138. Yoke 134 provides aconventional rotatable mounting for screw head 138, allowing rotation ofscrew 136 without an axial advancement thereof. Support arm 118 hassaddle-like threading engagement means 140 comprising a U-shaped platewhich engages two adjacent threads of screw 136. A tab 142 opposingsaddle 140 maintains threading engagement between support arm 118 andscrew 136, during screw rotation. As screw 136 is rotatably adjusted,support arm 118 is deflected in the direction of arrow 124, to move thebifurcated contact surfaces 130 in a direction transverse to path 104 sothat, on subsequent rotation of table 102, contact surfaces 130 engagedifferent points along the tapered leading edge 110 of contact 106. Thisadjustment in effect varies the length of the path along the contact 106travelled by finger-like contact 128, thereby controlling the timingduration of electrical engagement between contact members 106, 128.

Although a rotatable symmetrical switch assembly 100 is disclosed in thepreferred embodiment, table 102 could be mounted for reciprocal movementin a straight line or curved path to provide relative movement between afinger contact 128 and the contact plate 106. In any event, the leadingedge of contact 106 is tapered, such that when contact 128 is advancedin a transverse direction to path 104, different points along thetapered leading edge are engaged to provide a differential timingbetween the mating contact members.

What is claimed is:
 1. A stamped circuitry assembly including anintegral metal stamping having a plurality of discrete conductive paths,a dielectric substrate having complementary recesses for receiving saidconductive paths,the improvement comprising: said stamping alsoincluding an integrally formed snap action switch having an elongatedresilient spring plate with two parallel elongated spaced-apart slotstherein forming two outside support arms each including a pair of spacedoffset portions all extending in the same direction transverse to saidspring plate and an intermediate flexing arm, a first mounting end andan opposed second free end, contact carrying means at said second freeend, the switch further including actuator means deflecting a medialportion of the plate to displace the contact carrying means betweenfirst and second bistable positions, and said actuator means displacingsaid flexing arm in first and second directions generally transverse tothe spring plate, to cause differential bowing between said flexing armand said support arms, whereby said contact carrying means is displacedin said first and said second directions.
 2. A stamped circuitryassembly including an integral metal stamping having a plurality ofdiscrete conductive paths, a dielectric substrate having complementaryrecesses for receiving said conductive paths,the improvement comprising:said stamping also including an integrally formed snap action switchhaving an elongated resilient spring plate with two parallel elongatedspaced-apart slots therein forming two outside support arms and anintermediate flexing arm, a first mounting end and an opposed secondfree end, contact carrying means spaced from said mounting end; and theswitch further including actuator means deflecting a medial portion ofthe plate to displace the contact carrying means between first andsecond bistable positions, said actuator means comprising a rigid memberhaving first and second engaging surfaces disposed on either side ofsaid flexing arm, mounted for pivoting in a first direction to slidesaid first engaging surface along said flexing arm while deflecting saidflexing arm from a first to a second bistable position, and said rigidmember mounted for pivoting in a second opposed direction to impulsivelydeflect said flexing arm with said second engaging surface, from saidsecond to said first bistable position.